futures-cache

Futures-aware cache implementation backed by RocksDB.

State

The state of the library is: * API is limited to only wrap, which includes a timeout ([#1]). * Requests are currently racing in the wrap method, so multiple unecessary requests might occur when they should instead be queueing up ([#2]). * Entries only expire when the library is loaded ([#3]). * Only storage backend is RocksDB ([#4]).

Usage

This library requires the user to add the following dependencies to use:

toml futures-cache = "0.2.0" serde = {version = "1.0.97", features = ["derive"]} chrono = {version = "0.4.7", features = ["serde"]} rocksdb = "0.12.2"

You'll also have to install LLVM and clang since these are build dependencies for RocksDB. You can get them at: http://releases.llvm.org/download.html.

Examples

```rust use std::{path::Path, fs, error::Error, sync::Arc}; use rocksdb; use futures_cache::Cache; use futures; use chrono::Duration; use serde::{Serialize, Deserialize};

enum Key<'a> { /// Cache key for the get_user request. GetUser(&'a str), }

fn setup_db() -> Result, Box> { let path = Path::new("path/to/cache");

if !path.is_dir() {
    fs::create_dir_all(path)?;
}

let mut options = rocksdb::Options::default();
options.set_compression_type(rocksdb::DBCompressionType::Snappy);
options.set_keep_log_file_num(16);
options.create_if_missing(true);

Ok(Arc::new(rocksdb::DB::open(&options, path)?))

}

fn main() -> Result<(), Box> { let db = setup_db()?; let cache = Cache::load(db.clone())?; let api = Api::new()?;

futures::executor::block_on(async move {
    // Cache for 12 hours.
    let mary = cache.wrap(Key::GetUser("mary"), Duration::hours(12), api.get_user("mary")).await?;
    // Second request will be cached.
    let mary2 = cache.wrap(Key::GetUser("mary"), Duration::hours(12), api.get_user("mary")).await?;
});

} ```